Automated multi-step transmissions, designed as an automated manual transmission with a single input shaft and an assigned decoupler, designed as an automated dual-clutch with two input shafts assigned respectively to one of two partial transmissions, as well as with one decoupler respectively per input shaft, have been known in different designs for some time and have in part been used for several years in series-production vehicles.
The control device of an automated manual transmission comprises actuators, such as gear actuators for engaging and disengaging the gears, as well as a clutch actuator for engaging and disengaging the decoupler arranged in the power flow between the internal combustion engine and the input shaft of the transmission, as well as the control elements for controlling these actuators. In a similar manner, a control device of an automated dual-clutch transmission for each of the two partial transmissions comprises, in each case, actuators, such as gear actuators for engaging and disengaging the assigned gears and a clutch actuator for disengaging and engaging the assigned decoupler, as well as control elements for controlling the relevant actuators.
Due to high energy density, good control qualities, and the availability of technically perfected components, the control devices of automated manual transmissions and automated dual-clutch transmissions are usually constructed as hydraulic devices, in which the relevant gear actuators and clutch actuators are constructed as hydraulic actuating cylinders, and the assigned control elements as hydraulic selector or regulator valves. The gear-actuating cylinders can also be constructed as singly operating actuating cylinders, each having a single pressure chamber, which for engaging and disengaging a maximum of two gears assigned to one actuating rod, also requires two gear-actuating cylinders per actuating rod. The gear-actuating cylinders can, however, also be constructed as double-acting actuating cylinders with two pressure chambers each, in which case, for engaging and disengaging a maximum of two gears assigned to one actuating rod, only one gear-actuating cylinder per actuating rod is required.
The actuating and regulating valves can also be executed as directly controllable magnetic valves, and with this design, as directly actuated in each case by an electric control current. However, as this requires correspondingly strong electromagnets of relatively large dimensions and considerable weight, as well as comparatively high electric control currents, the actuating and regulating valves are preferably designed as pressure-controlled, and can, with this type of construction, be actuated by pilot valves that are usually designed as smaller magnetic valves. Particularly in the case of heavy commercial vehicles that are equipped with a pneumatic pressure-supply device for supplying energy to the pressure-accumulator brake system prescribed for this type of vehicle, a pneumatic construction of control devices for corresponding multi-step transmissions, with largely identical construction and the same functionality, is also possible as an alternative. That is why the present invention also includes pneumatic control devices, even though below, for the purpose of consistent formulation, only hydraulic control devices will be named.
A typical hydraulic control device of a dual-clutch transmission is described in DE 101 34 115 A1. In this known control device, a largely independent control branch is provided for each of the two partial transmissions. Each control branch features two gear-regulating valves respectively for controlling the operating pressure in each pressure chamber respectively by two assigned gear-actuating cylinders, each of which is double-acting, and one clutch control value for controlling the operating pressure in the assigned decoupler. The gear and clutch control valves are constructed as magnetic regulating valves, which are associated with the previously cited disadvantages of a large installation space requirement and high control current requirement.
In order to assign the gear control valves to the pressure chambers of the appropriate gear-actuating cylinders, a multiplex valve is provided, which is constructed as a singly switchable magnetic control valve with two shift positions. Using the multiplex valve, the operating pressure lines of the two gear-regulating valves are each alternately connected to the two pressure chambers of a single gear-actuating cylinder of the partial transmission concerned. With a mechanical or hydraulic coupling of the valve sections of both partial transmissions, there is, with a switchover of the multiplex valve, perforce a change in the assignment of the gear-regulating valves, in each case in both control branches at the same time. Due to its complicated construction, the multiplex valve is correspondingly large, expensive, and prone to malfunction. Furthermore, switches between two gears, which require a switchover of the multiplex valve, involve a correspondingly long temporal delay.
Another hydraulic control device of a dual-clutch transmission is known in a plurality of embodiments from DE 103 47 203 A1. In a first embodiment of this control device according to FIG. 40, a single gear-regulating valve with two controllable operating pressure lines is provided for controlling the operating pressure of two pressure chambers of a plurality of gear actuation cylinders. The gear-regulating valve is constructed here as a 4/3-way magnetic regulating valve. For the assignment of the gear-regulating valve to the gear-actuating cylinders of both partial transmissions, which are designed as double-acting actuating cylinders, a multiplex arrangement of a partial-transmission selector valve downstream of the gear-regulating valve and two cylinder selector valves downstream of that are provided. The selector valves are constructed respectively as singly switchable 8/2-way pressure-switch valves, whereby the cylinder selector valves are assigned respectively to the two gear-actuating cylinders of a partial transmission.
The shift position of the partial transmission selector valve determines the assignment of the gear-regulating valve to one of the two partial transmissions, and the shift position of the respective cylinder selector valve determines the assignment of the gear-regulating valve to one of the two gear-actuating cylinders of the partial transmission concerned. For actuation of the partial transmission selector valve, a pilot valve designed as a 3/2-way magnetic control valve is placed upstream of the selector valve. For actuation of the two cylinder selector valves, a common pilot valve designed as a 3/2-way magnetic control valve is provided.
Using the multiplex arrangement of simple and spacing-saving pressure-controlled selector valves results in advantages in terms of cost and installation space. The use of a single gear-regulating valve also has advantages compared with the aforesaid control device related to cost and installation space, but because of the coupled control of the operating pressure of both pressure chambers, it involves functional restrictions, and because of the electromagnetic control, there are certain disadvantages in terms of cost and installation space.
With a pressure-controlled variant of the embodiment of the gear-regulating valve according to FIG. 42 of DE 103 47 203 A1, at least referred to cost and installation-space disadvantages are eliminated. There, the pressure-controlled gear-regulating valve is actuated using an assigned pilot valve that is constructed as a magnetic regulating valve. Using two pressure-controlled gear-regulating valves according to FIG. 43 there enables independent control of the operating pressure of both pressure chambers, which improves the control characteristics of this known control device. There, the two pressure-controlled gear-regulating valves can be actuated in each case by means of an assigned pilot valve constructed in each case as a magnetic regulating valve.
Despite the cost and installation-space advantages and the functional advantages of the latter embodiment of the known control device, there is still a general need to make additional savings in cost and installation space as well as to improve the functional characteristics of a control device of this type.